Astronomers capture detailed images of Io’s lava lake

Chuck Bednar for – @BednarChuck

Using the Large Binocular Telescope Observatory (LBTO) in Arizona, researchers have for the first time captured detailed images of heat rising from the horseshoe-shaped lava lake on Io, the innermost moon of Jupiter, National Geographic reported on Thursday.

Thanks to the telescope, which features a pair of 8.4-meter mirrors, astronomers used imaging interferometry to capture the first detailed observations of the 125-mile (200 km) wide lava lake known as Loki. The images reveal that the feature is active, with multiple bright spots representing heat rising from its surface.

Loki, the largest of Io’s 300-plus volcanic features, is a volcanic depression known as a patera in which denser lava crust solidifying on top of a lava lake episodically sinks in the lake, LBTO experts said in a statement. This causes a rise in thermal emissions visible from Earth.

Gaining new insight into the Jovian moon

Loki is located approximately 600 million kilometers from Earth, and up until recently it was too small to be investigated in detail using ground-based optical or infrared telescopes. Thanks to the twin mirrors of the Large Binocular Telescope (LBT), however, it was captured in two images that were combined digitally into one 75-foot optical unit.

“We combine the light from two very large mirrors coherently so that they become a single, extremely, large mirror,” explained Al Conrad, lead investigator of a study published Thursday in The Astronomical Journal. “In this way, for the first time we can measure the brightness coming from different regions within the lake.”

Phil Hinz, head of the Large Binocular Telescope Interferometer (LBTI) project at the University of Arizona Steward Observatory, added that the discovery was the result of nearly 15 years worth of work. It was built “both to form sharp images, and to detect dust and planets around nearby stars at extremely high dynamic range,” he said, adding that it was “gratifying” to see it work so well.

Thanks to the instruments, the researchers can now identify different bright spots on the Loki patera – areas that they believe may represent individual lava flows or eruptions as the crust of the lake breaks apart and re-forms, according to National Geographic. In turn, those discoveries could solve some fundamental mysteries about Io’s orbit and internal structure.

Loki is the bright volcano on the left and Pele the other one on the lower right. (Credit: LBTO)

“Io’s highly elliptical orbit close to Jupiter is constantly tidally stressing the moon, like the squeezing of a ripe orange, where… [magma] can escape through cracks in the peel,” said team member Chick Woodward of the University of Minnesota.

“Studying the very dynamic volcanic activity on Io, which is constantly reshaping the moon ‘s surface, provides clues to the interior structure and plumbing of this moon, helping to pave the way for future NASA missions.”


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